An axle center height controller, which is also sometimes referred to as an axle center height control device, is a component of an axle load adjusting apparatus for tractor-trailer combinations. The axle load adjusting apparatus serves to change the center height of at least one axle of a semitrailer of the tractor-trailer combination, in particular a lifting axle, or to change the load taken up, and can be placed in a starting assistance mode.
The starting assistance mode is used to increase the weight acting on the drive axle, specifically, the drive-axle axle load, so that traction is improved. This enables the tractor-trailer combination to start more easily.
In order to protect public infrastructure, it is, typically, legally required that the axle load acting on an axle of the tractor-trailer combination not exceed a prescribed maximum axle load. In the European Union, for example, this maximum axle load is 130% of the nominal axle load, which is, itself, defined by the registration approval of the tractor-trailer combination.
A disadvantage with conventional axle center height controllers is that the tractor-trailer combinations equipped therewith start only with difficulty, in particular under tough ambient conditions and when they are fully loaded.